Sanitary napkin and method of manufacture



2 Sheets-Sheet 1 Oct. 8, 1963 E. DUDLEY SANITARY NAPKIN AND METHOD 0F MANUFACTURE Filed Jan. 3, 1961 Oct. 8, 1963 E. DUDLEY SANITARY NAPKIN AND METHOD OF MANUFACTURE 2 sheets-sheet '2 Filed Jan. 5, 1961 luga United States Patent Sylvania Filed Jan. 3, 1961;, Ser. No. @,251 6 Claims. (Ci. 12S-29o) The present invention relates `to sanitary napkins and particularly to a cover or Wrapper for a sanitary napkin.

Re-usable catamenial pads have been available for a long time but it was not until the early part of the present century that disposable sanitary napkins became popular, primarily because of the development of inexpensive absorbent materials, such as cellulose wadding, which provide a structure adequate for the purpose and which are so inexpensive that the napkin may be destroyed after a single use. In addition, because of machinery and technological developments of the early decades of the 20th century, high speed, inexpensive production of such disposable sanitary napkins became possible so that at the present time the disposable sanitary napkin is now a staple item of commerce and, indeed, some regard it as an absolute necessity.

Until recently, substantially no changes have been made in the structure, design and shape of the at pad-like napkin which is the most popular form of catamenial device. Unfortunately, the manufacturers of this type of napkin developed and offered for sale a flat, generally rectangular pad, the design of which bears no relation to the arrangement of the female anatomy in the area where the pad is to be worn. However, a recent improvement, illustrated by my co-pending application, Serial No. 745,544 tiled lune 30, 1958, and entitled Sanitary Napkin now U.S. Patent No. 2,973,760, provides a sanitary napkin designed speciiically to t the lfemale lbody around the genitalia, but the irregular shape and the structure of such napkin make it diiiicult to manufacture the napkin in the same manner or with the same materials and equipment as the old, iiat pads and still provide the maximum benefits which are attainable in such a napkin.

One disadvantage of napkins of the past relates to the method of constructing such pads. In the past, the dat, generally rectangular pads have been made by providing a rectangular batt, or a plurality of rectangular batts, f cellulose wadding or fluit, (highly absorbent creped paper) and such long, wide and flat batts were then encased in a cover which had to be both strong and pervious. The cover was merely a single piece wrapper encasing the batt much as one would wrap a package for mailing. Such wrapping method provided an undesirable longitudinal seam which extended the length of one side of the pad. 'Ihe wrapper, at its ends, protruded beyond the ends of the batt to for-rn and provide tabs used as securements to fasten the pad to a sanitary napkin belt. The single piece cover, if formed of a material having suicient strength to insure absolute reliability of the napkin in use, in general lacked one or more of such desirable properties as softness, perviousness, and absorbence or transmissibility. On the other hand, a single piece cover possessing all of these qualities could generally be expected to be made from a material having so little strength as to be unreliable.

Manufacturing methods involving the use of a single web of cover material have continued for many years, and in fact continue to date, principally because the thin, wide, rectangular pad per se, as well as the wrapping methods, are economical. However, though such wrapping methods may be employed with the trapezoidal or wedge-shaped pad, which is the subject of my Patent No.

ICC

2,973,760, the Vpresent invention provides a more desirable method for wrapping a thick, narrow batt of irregular shape to form a sanitary napkin designed specifically to it the female genitalia for its provides a structure comfortable to wear and which, because of its strength and adequate absorbency, assures the wearer of full protection. Such a pad and particularly the wrapper therefor are the subject of this present application.

With the foregoing considerations in mind, one object of the present invention is to provide an economical, smoothly-iitting cover or Wrapper for an irregularlyshaped sanitary napkin.

Another object of the present invention is to provide `a two piece cover for a sanitary napkin which aiiords a strong supporting portion on the side which does not contact lthe body and yet provides a soft, pervious and absorbent cover for the body-contacting side.

Another object of the present invention is to provide a cover for a sanitary napkin, and particularly an envelope for the absorbent iller material of the sanitary napkin, which cover or envelope consists of at least two, separate, distinct materials, one providing strength for holding the pad iirrnly in place on the body and the other providing a soft, pervious, body-contacting material.

Another object of the present invention is to provide a sanitary napkin in which shifting of the absorbent batt material within the cover is prevented.

Another object of the present invention is to provide a sanitary napkin cover, easily identiiiable by observation or by touch, which enables lthe user to determine which side of the napkin should be placed in contact with the body.

Another object of the present invention is to provide a sanitary napkin cover which is easily and rapidly manufactured in high :speed assembly lines and which does not require expensive and .complicated folding or pleating apparatus to provide a firm and compact encasement for the absorbent batt.

Another object of the present invention is to provide a rapid, eicient process for constructing a two piece sanitary napkin envelope or wrapper which affords an economical, high speed wrapping process for an irregularly-shaped sanitary napkin pad under conditions which insure a compact confinement of the pad within the wrapper :so `as to prevent shifting of the absorbent portion within the wrapper after assembly has been completed.

Other objects will be apparent by reference to the appended speciication, drawings and claims.

For the purpose of illustrating the invention, there is shown in the accompanying drawings a form thereof of which is at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangement and organization of the instrumentalities as herein shown and described.

With the foregoing considerations in mind, the present invention may be better comprehended by reference to the accompanying drawings wherein:

FIGURE 1 is a top perspective view of a sanitary napkin of the present invention.

FIGURE 2 is a bottom perspective view of the napkin.

FIGURES is a vertical cross-sectional view taken generally along line 3-3 of FIGURE 1.

FIGURE 4 is a vertical cross-sectional View taken generally along line 4A@ lof FIGURE 1.

FIGURE 5 is a vertical cross-sectional view taken generally `along line 5--5 of FIGURE l.

FIGURE 6 is a vertical cross-sectional view taken generally along line 6 6 of FIGURE 1.

FIGURE 7 is -a schematic drawing of a step-by-step process for covering an irregularly shaped pad according to the present invention; 7A being a view of the empty receptor, 7B a view tot the receptor having a soft porous cover-portion of the wrapper pushed thereinto by a pad which lis then carried along by the receptor, 7C being a view of the pad covered by the stronger supporting coverportion of the wrapper, and 7D a view of the pad after the edges of the cover-portion members have been sealed together, trimmed and folded and the pad removed from the receptor.

Referring now to the drawings, the numeral i@ indicates the sanitary napkin of the present invention which is substantially different in shape from the thin hat rectangular pads generally in use and can best be described as being irregular and preferably in the shape of a thick, narrow, long trapezoid as shown in -FlGURE 1. The napkin l@ includes a pad portion ll which is constructed of a plurality of layers of cellulose wadding or iiufl each of which layers is also trapezoidal in shape and provide an assembled bat-t which is highly absorbent but which is, per se, dirnensionally unstable and relatively weak. A water-proof barrier may be disposed generally medially in the pad l, as described in my Patent No. 2,973,760. The pad lll is enveloped by an envelope or cover l2 which comprises a top web i3 and a bottom web lli. Webs i3 and le cooperate in closely encasing the pad ll and pnoviding a strong support on the side thereof which does not contact the body while yet affording a soft, smooth pervious wrapper for the body-contacting portion.

As can be seen particularly in FGURES l, 3 and 6, the top or body-contacting web i3 fits snugly and tightly around the pad l1 and covers the top Aand side portions of the pad, Longitudinal extensions `of top web 13 provide the top portions of a wide tab l and a narrow tab 16, which extends longitudinally away from the pad ll and provide fastening means by which the napkin may be supported from a sanitary napkin belt or Aother suitable supporting means.

The bot-tom web 14 is relied upon to hold the napkin in place 4during use and yto withstand the forces exerted by the napkin belt or the pins connected to the tabs l5 and 16. As can be seen in the cross-sectional views of FIGURES 3, 4 and 5, the longitudinal edges vof the bottom supporting web le preferably are secured to the edges of the top web 13 to form longitudinal cover edges 1'7 which are folded beneath the pad and the tabs l5 and 16. In this construction the tob web r3 overlaps the bottom web lll so that there is very little chance of the strong but not-so-soft bottom web ld coming into contact with the body of the user, However, I do not mean tto limit myself to a structure wherein the marginal edges 17 are 4turned inwardly as shown in FGURE 3. By way of example, the top web 13 may be formed of nonwoven rayon fibers of `11/2 denier and approximately ll/z inches in length, which are lightly bonded together by means of a suitable adhesive. A web such as this is characterized by its softness, its light weight (of the order lof 1/2 ounce per square yard) and a relatively low tensile strength (of the order of 40 ounces per inch of width in the machine direction of the web). The bottom web may be formed of the same ray-on liber or filament material but given additional strength through the use of more fibers, the' application of additional bonding material or the application of reinforcing elements, such as rayon thread. A typical rayon thread reinforced web may exhibit strength in the machine direction of the order of 150 ounces per inch of width. Additionally, the bottom web lll may comprise a woven fabric selected for its duran bility and strength. rl`he bottom web Mr should exhibit strength particularly in its longitudinal direction for its principal action is to serve as a support for the pad lll of napkin lo. Because rthe bottom web lle is positioned and designed so as not to some into contact with the body of the user, it is not important that the material of the bottom web lli may be somewhat rougher than the texture of the top web i3. However, it is important that the top web i3 of the cover l2 be a soft, pervious material, having a pleasant feel and thus such material will generdly be weaker than the bottom web la. iowever, such lesser strength is not particularly critical for the principal purpose of the top web d3 is to contain the pad lil upon the bottom web i4, while the bottom web lill provides the strength `and supporting means for the assemblage. Additionally, it is important that the top cover be pervious so that it readily will pass the menstrual uids and permit the absorbent pad 1l effectively to receive and contain such deposit.

lt is obvious from the foregoing that identication of the top side will be readily achieved for the user can quickly detect the soft pervious web `l5 as the portion to be worn against the body thereby insuring the bottom web la will be positioned so as not to come in contact with the body of the user. Nevertheless, it may be desirable to identify the top web 13 by one color and the bottom web 14 by another color so as more readily to facilitate identification of the side of the pad which should be worn against the body. The provision of color idenftitication is facilitated by the use of two separate webs in constructing the cover l2. ln addition, the dierence in texture of :the top and bottom webs will make identification easy even if the pad is handled in the dark for, by sense of touch, the user can identify the softer top web i3 in the act of placing the pad in position against the body.

The top web i3 and the bottom web Ill are sealed together along marginal edges 17 either by the use of an adhesive or by the heat sealing characteristics of the material itself or in fact the two portions may be sewn together along the juncture points between the top web l3 and the bottom web E4 Where they meet in the marginal edge l. The marginal edges l? should not become stili' and interfere with the use of the pad or the comfort of the user while the pad is being worn. I have in mind that a thermoplastic materialsuch as for example polyethylene, properly selected to control the degree and type of bond obtainable, is particularly desirable for uniting the top and bottom Webs in the marginal edges l?. A thermoplastic adhesive manufactured by the United Shoe Machinery Company and sold under the trade name Thermogrip 1814 has been found to be particularly suitable in this application. Successful bonding has also been achieved utilizing special adhesives such as natural and synthetic latices.

Although l have illustrated some particular materials for webs 13 and ltd in the foregoing portions of this description, I do not mean to limit myself to any particular materials but can choose from a Wide variety of products which provide in the bottom web a strong supporting carrier portion of the cover while yet having in the top or body contacting portion a soft pervious material. Thus the wrapper of the present invention and the pad produced thereby distinguishes over previous similar structures where in a single wrapper element was used totally to encase the pad and thus either the strength of the supporting member had to be sacrificed in order to secure soft pervious qualities so desirable or else the desirable feel and texture of the body-contacting portion was sacrificed in order to secure suitable strength.

lt is to be noted that the utilization of a two piece cover olfers the additional advantage of permitting the napkin to be constructed so as to provide a smooth tightly fitting envelope for the pad and to provide fiat smooth tabs l5 and lo without pleating the cover to tuck the wrapper tightly against the pad ll. The top web 13 not only is soft, flexible, porous and absorbent but may be moldable and formable so that it tightly and smoothly fits about the contours of the pad lll and meets the bottom web llt only along the marginal edges 17 spaced closely along the sides of the pad il. and the side margins of the flitabs and 16. The bottom web 14 need be no wider than the width of the wide tab 15 plus twice the Width of an in-folded marginal edge 17, and, in fact, the bottom web 14 can be trimmed by suitable cutters so that the marginal edges 17 are no wider than is absolutely necessary to provide a secure bond between the top web 13 and the bottom web 14 at all portions along the length of the pad from the very tip of the wide tab 15 to the extreme end of the narrow tab 16.

It can thus be readily appreciated that regardless of the configuration of the pad 11, whether it be rectangular, trapezoidal or highly irregular in shape, the top web 13 of the cover 12 can be tightly and closely tted about the pad 11 by securing it to the bottom web 14 closely adjacent the marginal edges of the pad so that the pad 11 does not slip or move about within the cover 12 and thus the cover 12 securely positions the pad in place against the body of the user.

A method of assembling the pad is schematically illustrated in FIGURE 7 and from such drawing a basic and preferred principle of assemblage can be understood while yet appreciating that the mechanism which provides the assembly can be arranged in such a manner as toprovide high speed, efficient equipment capable of producingl the pads rapidly and economically. A carrier 18 is provided which has formed therein a plurality of receptors 19 which are shaped so as closely to receive the pad 11 therewithin, as is shown particuuarly in FIGURE 7A. The sides of the supporting carrier 18 may be movable or the carrier itself may be appropriately constructed so that the pads 11 may be fitted Within the receptor 19 easily and etiiciently from a supply means (not shown) which at the propitious moment deposits a pad 11 within a receptor 19.

However, before the pads 11 are placed within the receptors 19 a soft, exible, pervious top web 13 (the pads may preferably be formed in an upside down position) is laid upon the carrier 18 in such a manner that it covers the receptors 19. The web 18 may be fed from a suitable supply roll (not shown) and is laid upon the surface of the carrier 1S. A pad 11 is deposited upon the web, suitably oriented, so that it lies directly over a receptor 19, whereupon appropriate mechanism, such as a roller, may pass across the top of the pad 11 forcing it (and the web 13 directly therebeneath) into the receptor 19 in such a manner that the web 13 closely and carefully is drawn about the sides of the pad. The position of the pad and the web 13 within the receptor is shown in FIGURE 7B. If desired, the sides of the carrier adjacent the receptor may be convexly shaped so that the pad will not be compressed quite as flat as shown in FIGURE 7B. After the pad and the pervious top web 13 are positioned in the carrier 1S, the strong supporting bottom web 14 is fed to the top of the carrier from a suitable supply means (not shown) so that it overlies the pad and the top web 13 within the receptor 19 (see FIGURE 7C. Thereafter an appropriate sealing means such as a roller or other die can be passed across the top of the carrier 18 pressing tightly against the super-imposed top web 13 and bottom web 14 where it overlies the carrier 1S around the sides of the receptor 19, thus sealing the webs 13 and 14 together in the marginal Zones 17. If desirable, the two webs 13 and 14 may be sealed together in their entirety in the tab positions 16 and 17 although by judicious selection of the die or roller or sealing member, the two`webs 13 and 14 may be secured together only in the marginal edges 17 even where such portions extend along the sides of the tabs 146 and 17.

After the webs 13 and 14 have been securely sealed and the pad 11 encased in the cover 12, suitable trimming knives or shears (not shown) may remove the edge portions of the ywebs 13 and 14 fbeyond the marginal edges 17 and additionally the napkins may be trimmed to length so that the tabs 16 ,and 17 are of appropriate dimensions. Furthermore, the marginal edges 17 can then be folded inwardly to the position shown in FIG- URE 2.

The foregoing description of one form of assembling the pads is purely illustrative and it is to be understood that a plurality of receptors may be formed in a continuously moving carrier, such as a conveyor belt or a rotating wheel, so that the pads may be continuously fed into empty receptors, covered, sealed and removed in a continuous operation at high speed and with great efficiencies and economies.

An additional embodiment (not shown) includes the carrier web 14 disposed centrally of the pad 11, extending therethrough Iand into the tabs 16 and 17, with pads 11 on each side and each pad covered with soft web material 13.

The principal feature of the present invention, evident from the foregoing description, lis the provision of a cover or envelope lfor a sanita-ry .napkin which is made of two webs, -which construction greatly facilitates forming the cover to the configuration of the pad. The invention further contemplates the use of cover webs which are made from two different materials, one of which provides softness and perviousness for the body contacting portion of the napkin and the otherv of which provides strengthgiving support. The selection of materials to provide the maximum benefits also results in economies in material cost which cannot be obtained if a single piece cover is utilized.

My invention provides 'a highly satisfactory product which overcomes the principal disadvantages of covers heretofore provided for sanitary napkins, at less expense to lthe manufacturer, rand greater satisfaction to the user.

It is to be understood that the present invention may be embodied in other lspecific forms without departing from the spirit or essential attributes thereof Iand it is therefore desired that the present embodiments be `considered in all respects eas illustrative and therefore not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having described my invention, what I cltaim as new and desire to protect by Letters Patent is the following:

l. The method of forming a sanitary napkin having a two-piece cover for ian absorbent pad, which comprises taking oneweb which is la portion of the cover, disposing it overa receptor, placing a pad above the receptor :and above the web, pressing the pad and web into the receptor until the top of the pad is substantially flush with the top of the receptor, placing la web above the pad while it is disposed within the receptor and thereafter securely sealing lthe two webs together in an area around the pad and beyond the marginal limits thereof.

2. A sanitary napkin comprising at least two webs, one web being soft, pervious an'd relatively weak land the other web being strong in its longitudinal direction and a pad supported tbetween the two webs, said webs being united along the side margins of the pad and Ialso extending length-wise beyond each end of the =pad and being united along the margins of such extensions so as to provide tabs or support-members for the pad.

3. A sanitary napkin comprising an elongated absorbenft pad, a load-sustaining web yof flexible mlaterial covering one face of said pad and extending beyond the ends of the pad to provide support tabs for the pad, a soft, pervious and relatively weak web covering the remainder of said pad and extending beyond the ends of the pa-d substantially co-extensively with the load-sustaining web, and means securing said webs together with the pad therebetween, said soft web constituting the body contacting surface of the napkin, whereby only said soft web is in contact with the body when said napkin is in use.

4. A sanitary napkin `las defined by claim 3, wherein said means for securing said webs together comprises longitudinal strips of adhesive alongside of said pad.

6. A sanitary napkin' as defined by claim 4 in which longitudinal edge portions of said webs are folded bask on said load-sustaining web whereby the outer longitudinal regions of .said load-sustaining web are covered by said soft web.

References @lied in the le of this paent UNITED STATES PATENTS Voigtman July 28, 1959 Ashton Dec. 13, 1969 Dudley Mar. 7, 1961 

2. A SANITARY NAPKIN COMPRISING AT LEAST TWO WEBS, ONE WEB BEING SOFT, PERVIOUS AND RELATIVELY WEAK AND THE OTHER WEB BEING STRONG IN ITS LONGITUDINAL DIRECTION AND A PAD SUPPORTED BETWEEN THE TWO WEBS, SAID WEBS BEING UNITED ALONG THE SIDE MARGINS OF THE PAD AND ALSO EXTENDING LENGTH-WISE BEYOND EACH END OF THE PAD AND BEING UNITED 